A research group for the National Institute for Environmental Studies (NIES) has been studying the use of bacteria in the measurement and decontamination of radioactive cesium. The group cultured bacteria in soil and investigated its cesium accumulation ability, confirming that about one-tenth of the bacteria in the soil were able accumulate cesium.

The group then placed the cesium-accumulating bacteria into a dialysis tube, which was immersed it in an aqueous solution containing radioactive cesium. The concentration of radioactive cesium in the solution decreased over time, reaching 25 percent of the initial concentration at 32 hours. At this point, the radioactive cesium present in the cells was 7,500-fold higher than the initial concentration of the solution.

The cesium-accumulating bacteria are likely to simplify the concentrating process, as a concentrating operation is required to measure radioactive cesium contamination. Similar concentration methods using the accumulation ability of microorganisms have been applied to the removal of phosphorus from wastewater using bacteria and the concentration of uranium in sea water using yeast.

Dr. Noriko Tomioka, a senior researcher, notes that challenges remain before the practical use of the cesium-accumulating bacteria, as they cannot be used in sea water and also subject to constraints on temperature and acidity. However, their approach is hoped to offer a method for eliminating radioactive materials amid the ongoing radiation issues caused by the Fukushima nuclear power plant accident.